Labour leader Ed Miliband does a selfie in Cambridge. Is it time for a citizens' question time? Photograph: Stefan Rousseau/PA

Ed Miliband’s proposal for a citizens’ question time, in which voters as well as MPs are able to interrogate the prime minister in parliament on a regular basis, deserves to be taken seriously. The opposition leader’s underlying argument is an entirely logical one, and will be widely understood. A large section of the public feels alienated from the political system. The system has a responsibility to respond to that alienation. A regular questioning session of the prime minister by members of the public could be part of the necessary process of rebuilding institutional confidence. If, as a byproduct, it helps to boost Mr Miliband’s flagging ratings, then that’s no reason to dismiss the idea, least of all for the Labour party.

Compared with, say, bankers or journalists, politicians are role models when it comes to responding to public criticism. But reforms of this kind are not just good for politicians. They are also, potentially, good for parliament. This is another big reason for taking Mr Miliband’s idea seriously. Faced with complaints about politics, politicians have responded by doing webchats and radio phone-ins – even, in one or two cases, reviving the lost art of the public meeting. Such initiatives are all worthy stuff. But they only benefit parliament indirectly. Citizens’ question time might help to revive confidence in the House of Commons as an institution. This would be a more lasting achievement.

Practical problems would need solving. When? The most practical time would be straight after prime minister’s questions from MPs. Where? In the palace of Westminster or nearby, but with a proper level of formality – the questioners physically present, the Speaker not Evan Davis in the chair, and the exchanges recorded in Hansard. Most important of all – who? It would be vital to stop the parties packing the process with tame supporters. First-come-first-served in SW1 would favour Londoners; the sessions, like parliament, could move around the country. Selection by lot – similar to the process for selecting courtroom juries – is the fairest and best way.

On its own, though, opening-up of questioning is not going to get very far. Prime ministers since Tony Blair have had regular sessions with select committee chairs and held regular press conferences; these have not transformed the public’s mood. Democracy in Britain needs a bigger revolution of institutions, practices and mentalities. This means, among other things, that Lords reform, empowering backbenchers, devolution and the Leveson report all need to be on the agenda, along with consideration of ideas citizens’ juries and reform of political funding. Letting the public ask the questions would let in more sunlight, but it would be naive to suppose it would usher in Plato’s republic too.